This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.

Overflow Buffers

Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an attacker. As a consequence, an attacker is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the attackers' choice.

Client-side Injection-induced Buffer Overflow

This type of attack exploits a buffer overflow vulnerability in targeted client software through injection of malicious content from a custom-built hostile service.

Filter Failure through Buffer Overflow

In this attack, the idea is to cause an active filter to fail by causing an oversized transaction. An attacker may try to feed overly long input strings to the program in an attempt to overwhelm the filter (by causing a buffer overflow) and hoping that the filter does not fail securely (i.e. the user input is let into the system unfiltered).

MIME Conversion

An attacker exploits a weakness in the MIME conversion routine to cause a buffer overflow and gain control over the mail server machine. The MIME system is designed to allow various different information formats to be interpreted and sent via e-mail. Attack points exist when data are converted to MIME compatible format and back.

Overflow Binary Resource File

An attack of this type exploits a buffer overflow vulnerability in the handling of binary resources. Binary resources may include music files like MP3, image files like JPEG files, and any other binary file. These attacks may pass unnoticed to the client machine through normal usage of files, such as a browser loading a seemingly innocent JPEG file. This can allow the attacker access to the execution stack and execute arbitrary code in the target process. This attack pattern is a variant of standard buffer overflow attacks using an unexpected vector (binary files) to wrap its attack and open up a new attack vector. The attacker is required to either directly serve the binary content to the victim, or place it in a locale like a MP3 sharing application, for the victim to download. The attacker then is notified upon the download or otherwise locates the vulnerability opened up by the buffer overflow.

Buffer Overflow via Symbolic Links

This type of attack leverages the use of symbolic links to cause buffer overflows. An attacker can try to create or manipulate a symbolic link file such that its contents result in out of bounds data. When the target software processes the symbolic link file, it could potentially overflow internal buffers with insufficient bounds checking.

Overflow Variables and Tags

This type of attack leverages the use of tags or variables from a formatted configuration data to cause buffer overflow. The attacker crafts a malicious HTML page or configuration file that includes oversized strings, thus causing an overflow.

Buffer Overflow via Parameter Expansion

In this attack, the target software is given input that the attacker knows will be modified and expanded in size during processing. This attack relies on the target software failing to anticipate that the expanded data may exceed some internal limit, thereby creating a buffer overflow.

Buffer Overflow in an API Call

This attack targets libraries or shared code modules which are vulnerable to buffer overflow attacks. An attacker who has access to an API may try to embed malicious code in the API function call and exploit a buffer overflow vulnerability in the function's implementation. All clients that make use of the code library thus become vulnerable by association. This has a very broad effect on security across a system, usually affecting more than one software process.

Buffer Overflow in Local Command-Line Utilities

This attack targets command-line utilities available in a number of shells. An attacker can leverage a vulnerability found in a command-line utility to escalate privilege to root.

From Red Hat Security Advisory 2017:2389 :
An update for freeradius is now available for Red Hat Enterprise Linux 7.
Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.
FreeRADIUS is a high-performance and highly configurable free Remote Authentication Dial In User Service (RADIUS) server, designed to allow centralized authentication and authorization for a network.
Security Fix(es) :
* An out-of-bounds write flaw was found in the way FreeRADIUS server handled certain attributes in request packets. A remote attacker could use this flaw to crash the FreeRADIUS server or to execute arbitrary code in the context of the FreeRADIUS server process by sending a specially crafted request packet. (CVE-2017-10984)
* An out-of-bounds read and write flaw was found in the way FreeRADIUS server handled RADIUS packets. A remote attacker could use this flaw to crash the FreeRADIUS server by sending a specially crafted RADIUS packet. (CVE-2017-10978)
* An out-of-bounds read flaw was found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use this flaw to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10983)
* A denial of service flaw was found in the way FreeRADIUS server handled certain attributes in request packets. A remote attacker could use this flaw to cause the FreeRADIUS server to enter an infinite loop, consume increasing amounts of memory resources, and ultimately crash by sending a specially crafted request packet. (CVE-2017-10985)
* Multiple out-of-bounds read flaws were found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use these flaws to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10986, CVE-2017-10987)
Red Hat would like to thank the FreeRADIUS project for reporting these issues. Upstream acknowledges Guido Vranken as the original reporter of these issues.

An update for freeradius is now available for Red Hat Enterprise Linux 7.
Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.
FreeRADIUS is a high-performance and highly configurable free Remote Authentication Dial In User Service (RADIUS) server, designed to allow centralized authentication and authorization for a network.
Security Fix(es) :
* An out-of-bounds write flaw was found in the way FreeRADIUS server handled certain attributes in request packets. A remote attacker could use this flaw to crash the FreeRADIUS server or to execute arbitrary code in the context of the FreeRADIUS server process by sending a specially crafted request packet. (CVE-2017-10984)
* An out-of-bounds read and write flaw was found in the way FreeRADIUS server handled RADIUS packets. A remote attacker could use this flaw to crash the FreeRADIUS server by sending a specially crafted RADIUS packet. (CVE-2017-10978)
* An out-of-bounds read flaw was found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use this flaw to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10983)
* A denial of service flaw was found in the way FreeRADIUS server handled certain attributes in request packets. A remote attacker could use this flaw to cause the FreeRADIUS server to enter an infinite loop, consume increasing amounts of memory resources, and ultimately crash by sending a specially crafted request packet. (CVE-2017-10985)
* Multiple out-of-bounds read flaws were found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use these flaws to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10986, CVE-2017-10987)
Red Hat would like to thank the FreeRADIUS project for reporting these issues. Upstream acknowledges Guido Vranken as the original reporter of these issues.

Security Fix(es) :
- An out-of-bounds write flaw was found in the way FreeRADIUS server handled certain attributes in request packets. A remote attacker could use this flaw to crash the FreeRADIUS server or to execute arbitrary code in the context of the FreeRADIUS server process by sending a specially crafted request packet. (CVE-2017-10984)
- An out-of-bounds read and write flaw was found in the way FreeRADIUS server handled RADIUS packets. A remote attacker could use this flaw to crash the FreeRADIUS server by sending a specially crafted RADIUS packet.
(CVE-2017-10978)
- An out-of-bounds read flaw was found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use this flaw to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10983)
- A denial of service flaw was found in the way FreeRADIUS server handled certain attributes in request packets. A remote attacker could use this flaw to cause the FreeRADIUS server to enter an infinite loop, consume increasing amounts of memory resources, and ultimately crash by sending a specially crafted request packet.
(CVE-2017-10985)
- Multiple out-of-bounds read flaws were found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use these flaws to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10986, CVE-2017-10987)

An update for freeradius is now available for Red Hat Enterprise Linux 7.
Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.
FreeRADIUS is a high-performance and highly configurable free Remote Authentication Dial In User Service (RADIUS) server, designed to allow centralized authentication and authorization for a network.
Security Fix(es) :
* An out-of-bounds write flaw was found in the way FreeRADIUS server handled certain attributes in request packets. A remote attacker could use this flaw to crash the FreeRADIUS server or to execute arbitrary code in the context of the FreeRADIUS server process by sending a specially crafted request packet. (CVE-2017-10984)
* An out-of-bounds read and write flaw was found in the way FreeRADIUS server handled RADIUS packets. A remote attacker could use this flaw to crash the FreeRADIUS server by sending a specially crafted RADIUS packet. (CVE-2017-10978)
* An out-of-bounds read flaw was found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use this flaw to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10983)
* A denial of service flaw was found in the way FreeRADIUS server handled certain attributes in request packets. A remote attacker could use this flaw to cause the FreeRADIUS server to enter an infinite loop, consume increasing amounts of memory resources, and ultimately crash by sending a specially crafted request packet. (CVE-2017-10985)
* Multiple out-of-bounds read flaws were found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use these flaws to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10986, CVE-2017-10987)
Red Hat would like to thank the FreeRADIUS project for reporting these issues. Upstream acknowledges Guido Vranken as the original reporter of these issues.

According to the versions of the freeradius package installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :
- An integer overflow leading to a heap-buffer overflow was found in the libnl library. An attacker could use this flaw to cause an application compiled with libnl to crash or possibly execute arbitrary code in the context of the user running such an application.
(CVE-2017-0553)
- An out-of-bounds read and write flaw was found in the way FreeRADIUS server handled RADIUS packets. A remote attacker could use this flaw to crash the FreeRADIUS server by sending a specially crafted RADIUS packet.
(CVE-2017-10978)
- A denial of service flaw was found in the way FreeRADIUS server handled certain attributes in request packets. A remote attacker could use this flaw to cause the FreeRADIUS server to enter an infinite loop, consume increasing amounts of memory resources, and ultimately crash by sending a specially crafted request packet. (CVE-2017-10985)
- Multiple out-of-bounds read flaws were found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use these flaws to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10986, CVE-2017-10987)
- An out-of-bounds read flaw was found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use this flaw to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10983)
- Multiple out-of-bounds read flaws were found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use these flaws to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10986, CVE-2017-10987)
- An out-of-bounds write flaw was found in the way FreeRADIUS server handled certain attributes in request packets. A remote attacker could use this flaw to crash the FreeRADIUS server or to execute arbitrary code in the context of the FreeRADIUS server process by sending a specially crafted request packet. (CVE-2017-10984)
Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the versions of the freeradius package installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :
- An integer overflow leading to a heap-buffer overflow was found in the libnl library. An attacker could use this flaw to cause an application compiled with libnl to crash or possibly execute arbitrary code in the context of the user running such an application.
(CVE-2017-0553)
- An out-of-bounds read and write flaw was found in the way FreeRADIUS server handled RADIUS packets. A remote attacker could use this flaw to crash the FreeRADIUS server by sending a specially crafted RADIUS packet.
(CVE-2017-10978)
- A denial of service flaw was found in the way FreeRADIUS server handled certain attributes in request packets. A remote attacker could use this flaw to cause the FreeRADIUS server to enter an infinite loop, consume increasing amounts of memory resources, and ultimately crash by sending a specially crafted request packet. (CVE-2017-10985)
- Multiple out-of-bounds read flaws were found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use these flaws to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10986, CVE-2017-10987)
- An out-of-bounds read flaw was found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use this flaw to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10983)
- Multiple out-of-bounds read flaws were found in the way FreeRADIUS server handled decoding of DHCP packets. A remote attacker could use these flaws to crash the FreeRADIUS server by sending a specially crafted DHCP request. (CVE-2017-10986, CVE-2017-10987)
- An out-of-bounds write flaw was found in the way FreeRADIUS server handled certain attributes in request packets. A remote attacker could use this flaw to crash the FreeRADIUS server or to execute arbitrary code in the context of the FreeRADIUS server process by sending a specially crafted request packet. (CVE-2017-10984)
Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Guido Vranken discovered that FreeRADIUS incorrectly handled memory when decoding packets. A remote attacker could use this issue to cause FreeRADIUS to crash or hang, resulting in a denial of service, or possibly execute arbitrary code.
Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Guido Vranken discovered that FreeRADIUS, an open source implementation of RADIUS, the IETF protocol for AAA (Authorisation, Authentication, and Accounting), did not properly handle memory when processing packets. This would allow a remote attacker to cause a denial-of-service by application crash, or potentially execute arbitrary code.
All those issues are covered by this single DSA, but it's worth noting that not all issues affect all releases :
- CVE-2017-10978 and CVE-2017-10983 affect both jessie and stretch;
- CVE-2017-10979, CVE-2017-10980, CVE-2017-10981 and CVE-2017-10982 affect only jessie;
- CVE-2017-10984, CVE-2017-10985, CVE-2017-10986 and CVE-2017-10987 affect only stretch.